German Translation: SMS delivery notification

Changed the SMS delivery notification translation, so it doesn't imply that you have just received a message.
I also submitted this to the official Android gerrit, but it has not been verified until now. ( https://android-review.googlesource.com/#/c/61961/ )

Change-Id: I86a47b4689dad9e71da6ad7d90794da39c3834d7